Lineba 110V To 220V Step Up Down Power Voltage Converter Watt Transformer For Travel (100W)Instruction: BR Before using this adapter please make sure which voltage you need, by checking the switchs place at the bottom of it BR That is:BR A, switch to Ac117V, input voltage must be Ac110120V, voltage converter (output) Ac220240V BR B, switch to Ac23..